猪流行性腹泻病毒入侵细胞的研究进展

猪流行性腹泻病毒(Porcine epidemic diarrhea virus,PEDV)对新生仔猪危害极大,致死率可达90%,该病毒的变异株自2010年在中国乃至世界大规模暴发后,给养猪业造成巨大经济损失,本文总结了PEDV进入宿主细胞的研究进展,包括PEDV S蛋白在病毒入侵中的作用,以及PEDV在入侵过程中猪氨基肽酶N和唾液酸的作用,以此为PEDV致病机理的研究和该病防控提供基础和思路。

轮状病毒入侵细胞机制的研究进展

轮状病毒(Rotavirus,RV)是引起婴幼儿腹泻死亡的主要病原体之一,是一种没有外膜的RNA病毒,由3层同心的蛋白质衣壳包被双链RNA基因组构成。RV入侵宿主细胞是一个有机的多步骤过程,有多种受体参与,其作用机理还不完全清楚,目前认为,病毒与宿主细胞表面受体之间至少存在4种相互作用关系。

入侵脑细胞

为了挽救被关押的幸存女孩，儿童临床医学家凯瑟琳·迪恩用现代高科技进入到昏迷的杀手大脑中，进入杀人凶手的灵魂，开始了一次奇异未知并且充满危险的旅程……这是美国电影科幻惊悚片《入侵脑细胞》所讲述的故事。

丙型肝炎病毒的细胞入侵和相关受体

丙型肝炎病毒(hepatitisCvirus,HCV)入侵细胞的过程由多种细胞受体介导,目前已鉴定出人CD81、SR-BI、LDLr、L-SIGN、DC-SIGN、ASGPR、Claudin-1等为HCV的受体。对HCV入侵机制的研究,有助于对HCV入侵的各个环节进行阻断和干预,从而达到预防或/和治疗的目的。近年来,HCVpp及HCVcc模型的建立为HCV入侵细胞的研究提供了重要平台。该文从HCV细胞入侵的研究模型、HCV的细胞受体和HCV入侵细胞的影响因素三方面,综述HCV细胞入侵的研究进展。

乙型脑炎病毒入侵细胞的分子机制研究进展

乙型脑炎病毒(Japanese encephalitis virus,JEV)是一种蚊媒病毒,能引发严重的病毒性脑炎。JEV入侵细胞是致病的先决条件,因此阐明其机制可为乙型脑炎的治疗提供更多途径。本文就近年来JEV入侵细胞的分子机制研究进展作一综述。

细胞极性与丙型肝炎病毒受体介导的细胞入侵

丙型肝炎病毒(hepatitis C virus,HCV)的细胞入侵过程由多因素介导,包括多种受体及触发病毒内吞入胞的细胞因素。新发现的受体分子occludin已被证明与SR-B1、CD81、claudin同介导HCV细胞入侵,occludin和claudin同为组成细胞间紧密连接的整合蛋白,引起了研究者们对紧密连接及细胞极性对HCV入侵影响的广泛关注。对细胞极性及紧密连接的研究,有助于发现新的HCV治疗药物的作用靶点,从而干预其细胞入侵及细胞间蔓延。本文从肝细胞极性特点、紧密连接及主要整合蛋白claudin和occludin、极性细胞模型及与HCV入侵的关系等几个方面综述了近来的最新进展。

电影《入侵脑细胞》的精神分析解读

电影《入侵脑细胞》(The Cell)具有商业片的典型特征,但影片在科幻背景的设置下,融入超现实主义艺术要素,结合弗洛伊德精神分析学理论进行创作,具备不同于普通商业片的欣赏价值。本文结合弗洛伊德的意识层次理论、人格结构理论和本能理论,从影片中的重要意象——玩偶入手,结合卡尔孩提时代的不幸经历,对他谋杀女性的原因、自我拯救的尝试、被拯救的过程进行分析,从而对影片的拯救主题进行解读。

闭合蛋白-1衍生肽抑制丙型肝炎病毒入侵

丙型肝炎病毒（HCV）入侵是一个需要多种宿主因子参与的复杂过程，如CD81、清道夫受体B1、封闭蛋白-1（CLDN1）和密封蛋白（occludin）。病毒和细胞入侵因子之间的相互作用为新型抗HCV药物的开发提供了潜在靶点。

单增李斯特菌内化素A分段表达及多克隆抗体的制备

为了研究单增李斯特茵（Listeria monocytogenes）InlA蛋白入侵细胞时各段相关功能，试验采用PCR技术扩增得到L．monocytogenes 08—5923株InlA基因片段，测序后利用GenBank对InlA氨基酸序列进行分段，分为2个基因片段，即InlAl（1-1488bp）和InlA2（1315—2403bp），将其分别克隆至原核表达载体pGEX-6P-1中，并转化至宿主茵中诱导表达，表达的重组蛋白经Western—blot和间接ELISA法鉴定，用纯化的重组蛋白分别免疫家兔，并用ELISA法检测家兔多克隆抗体的特异性。结果表明：表达的2种重组蛋白分子质量分别约为79ku和64ku，以其制备的多克隆抗体均可与单增李斯特茵InlA天然蛋白发生反应；2种重组蛋白均能有效诱导抗体反应，其中InlA2（new flag）诱导产生的抗体效价较高，与单增李斯特茵InlA天然蛋白结合能力较强。

鸡白痢沙门氏菌orgC基因缺失株的构建及生物被膜形成特性研究

为探索鸡白痢沙门氏菌Ⅲ型分泌系统效应蛋白OrgC在生物被膜形成中的作用,试验以鸡白痢沙门氏菌S9及其rpoS基因缺失株S9S为母本,利用Red同源重组系统构建orgC基因缺失株并利用原核表达载体构建回复株,测定其生物被膜形成能力和对鸡肝癌(Leghorn male hepatoma,LMH)细胞黏附入侵能力。结果显示:orgC基因缺失株生物被膜形成能力与野生株S9相比无显著变化,rpoS和orgC双基因缺失株生物被膜形成能力与rpoS基因缺失株S9S相比显著降低(P<0.05);orgC基因缺失株对LMH细胞入侵能力与野生株S9相比无显著变化,rpoS和orgC双基因缺失株对LMH细胞入侵能力与rpoS基因缺失株S9S相比显著降低(P<0.05)。研究表明,Ⅲ型分泌系统效应蛋白OrgC与鸡白痢沙门氏菌生物被膜形成及细胞入侵能力有关。

丙型肝炎的致病机制及药物治疗

丙型肝炎(丙肝)病毒(hepatitis C virus,HCV)可以通过几种途径影响宿主免疫功能,使病毒在宿主细胞内持续复制,最终导致HCV慢性感染。目前治疗慢性丙肝的方法主要是聚乙二醇干扰素和利巴韦林联合用法,此种疗法在HCV1型患者中约50%不能产生持续病毒学应答,且有不良反应。近年来,随着对HCV复制以及病毒非结构蛋白功能的深入研究,针对减少HCV载量的特异性药物的研发取得了较大进展。本文就HCV的细胞入侵、复制、逃避宿主的固有和获得性免疫及抗HCV临床试验药物的最新进展进行综述。

猪δ冠状病毒致病机制研究进展

猪δ冠状病毒(PDCoV)是引起猪腹泻性疾病的猪肠道主要病毒之一。PDCoV致病机制相关的研究主要集中于入侵细胞、逃逸宿主细胞天然免疫应答、诱导宿主细胞凋亡,以及影响该病毒复制的其他分子机制。目前对其致病机制的了解较少,尚无有效防治该病毒的疫苗和药物。随着相关研究进一步深入,剖析PDCoV编码蛋白结构及其影响PDCoV复制的多种途径,探索影响PDCoV复制的miRNA及相关分子机制,或可为深入认识PDCoV致病机制及研制有效防治该病毒的疫苗和药物提供重要理论依据。此外,对不同冠状病毒之间致病机制的共性与特性进行比较研究,也将对冠状病毒的抗病毒药物或疫苗的研制具有重要意义。

Effect of norcantharidin on proliferation and invasion of human gallbladder carcinoma GBC-SD cells

AIM: To investigate the effect of norcantharidin on proliferation and invasion of human gallbladder carcinoma GBC-SD cells in vitro and its anticancer mechanism. METHODS: Human gallbladder carcinoma GBC-SD cells were cultured by cell culture technique. The growth and the invasiveness of GBC-SD cells in vitro were evaluated by the tetrazolium-based colorimetric assay and by the Matrigel experiment and the crossing-river test. Expression of PCNA, Ki-67, MMP2 and TIMP2 proteins of GBC-SD cells was determined by streptavidin-biotin complex method. RESULTS: In vitro norcantharidin inhibited the growth and proliferation of GBC-SD cells in a dose- and time-dependent manner, with the IC50 value of 56.18 μ/mL at 48 h. Norcantharidin began to inhibit the invasion of GBC-SD cells at the concentration of 5 μg/mL, and the invasive action of GBC-SD cells was inhibited completely and their crossing-river time was prolonged significantly at 40 μg/mL. After treatment with norcantharidin, the expression of PCNA, Ki-67, and MMP2 was significantly decreased. With the increase in TIMP2 expression, the MMP2 to TIMP2 ratio was decreased significantly (P<0.05). CONCLUSION: Norcantharidin inhibits the proliferation and growth of human gallbladder carcinoma cells in vitro at relatively low concentrations by inhibiting PCNA and Ki-67 expression. Its anti-invasive activity may be the result of decrease in MMP2 to TIMP2 ratio and reduced cell motility.

鼠伤寒沙门菌中假定转录调控因子的筛选

目的·基因组信息学分析结合分子生物学实验对鼠伤寒沙门菌中假定转录调控因子进行筛选,以期发现新的转录调控因子和调控机制。方法·通过沙门菌基因组信息分析筛选得到30个假定转录调控因子,利用λ-Red同源重组系统敲除各目的基因。酸耐受实验检测各敲除株在对数期酸耐受应答中的差异;细胞感染模型检测各敲除株上皮细胞入侵能力和巨噬细胞内复制能力;利用realtimePCR检测突变株中pho P及其下游基因的转录水平。结果·成功构建30个敲除株。ΔSTM14_0739、ΔSTM14_2717和ΔSTM14_1646对数期酸耐受能力较WT增强,ΔSTM14_1878、ΔSTM14_4338和ΔSTM14_1965则较WT减弱。ΔSTM14_0739和ΔSTM14_2717对He La细胞的入侵率降低,ΔSTM14_1878和ΔSTM14_2717在RAW264.7细胞内的24 h复制率提高。Realtime-PCR结果显示STM14_2717敲除并不影响pho P转录。结论·研究发现了新的转录调控因子,为深入研究沙门菌致病机制提供新的方向。

MicroRNA-21 targets tumor suppressor genes in invasion and metastasis

MicroRNAs （miRNAs） are a class of naturally occurring small non-coding RNAs that target protein-coding mRNAs at the post-transcriptional level. Our previous studies suggest that mir-21 functions as an oncogene and has a role in tumorigenesis, in part through regulation of the tumor suppressor gene tropomyosin 1 （TPM1）. Given that TPM1 has been implicated in cell migration, in this study we further investigated the role of mir-21 in cell invasion and tumor metastasis. We found that suppression of mir-21 in metastatic breast cancer MDA-MB-231 cells significantly reduced invasion and lung metastasis. Consistent with this, ectopic expression of TPM1 remarkably reduced cell invasion. Furthermore, we identified two additional direct mir-21 targets, programmed cell death 4 （PDCD4） and maspin, both of which have been implicated in invasion and metastasis. Like TPM1, PDCD4 and maspin also reduced invasiveness of MDA-MB-231 cells. Finally, the expression of PDCD4 and maspin inversely correlated with mir-21 expression in human breast tumor specimens, indicating the potential regulation of PDCD4 and maspin by mir-21 in these tumors. Taken together, the results suggest that, as an oncogenic miRNA, mir-21 has a role not only in tumor growth but also in invasion and tumor metastasis by targeting multiple tumor/metastasis suppressor genes. Therefore, suppression of mir-21 may provide a novel approach for the treatment of advanced cancers.

Inhibitory effect of dimeric β peptide on the recurrence and metastasis of hepatocellular carcinoma in vitro and in mice

AIM:To block the adhesion of tumor cells to the extra- cellular matrix, and prevent tumor metastasis and recur- rence, the dimer of the β peptide (DLYYLMDLSYSMKG- GDLYYLMDLSYSMK, β2) was designed and synthesized and its anti-adhesion and anti-invasion effects on hepa- tocellular carcinoma cells were assessed. Additionally, its influence on the metastasis and recurrence of mouse hepatocellular carcinoma was measured. METHODS:The anti-adhesion effect of β2 on the highly metastatic hepatocellular carcinoma cell line HCCLM6 cells and fibronectin (FN) was assayed by the MTT as- say. The inhibition of invasion of HCCLM6 cells by β2 was observed using a Transwell (modified Boyden chamber) and matrigel. Using the hepatocellular carcinoma metas- tasis model and LCI-D20 nude mice, the influence of β2 on the metastasis and recurrence of hepatocellular carci- noma after early resection was investigated. RESULTS:HCCLM6 cells co-incubated with 100 mmol/L, 50 mmol/L, 20 mmol/L or 10 mmol/L β2 for 3 h showed an obvious decrease in adhesion to FN. The adhesion inhibition ratios were 11.8%, 21.7%, 29.6% and 48.7%, respectively. Additionally, HCCLM6 cells cultured with 100 mmol/L β2 had a dramatic decrease in cell invasion. β2 was also observed to inhibit the incisal edge recur- rence and the distant metastasis of nude mice hepato- cellular carcinoma after early resection (P < 0.05). CONCLUSION:The β2 peptide can specifically block the adhesion and invasion of HCCLM6 cells, and can inhibit HCC recurrence and metastasis of LCI-D20 model pos-thepatectomy in vivo. Thus, β2 should be further studied as a new anti-tumor drug.

Crosstalk between tumor cells and microenvironment via Wnt pathway in colorectal cancer dissemination

Invasion and metastasis are the deadly face of malignant tumors. Considering the high rate of incidence and mortality of colorectal cancer, it is critical to determine the mechanisms of its dissemination. In the parallel investigation of the invasive front and tumor center area of colorectal cancer (CRC), observation of heterogeneous β-catenin distribution and epithelial-mesenchymal transition (EMT) at the invasive front suggested that there might be a crosstalk between tumor cells and the tumor microenvironment. Wnt signaling pathway is also involved in the cancer progression due to its key role in CRC tumorigenesis. Moreover, in recent years, there is increasing evidence that the regulators of microenvironment, including extracellular matrix, growth factors and inflammatory factors, are associated with the activation of Wnt pathway and the mobility of tumor cells. In this review, we will try to explain how these molecules trigger metastasis via the Wnt pathway.

Growth process of small pancreatic carcinoma: A case report with imaging observation for 22 months

This report describes serial observations of the growth process of a small invasive ductal carcinoma (IDC) of the pancreas from imaging studies. Histopathological studies showed IDC with macroscopic retention cysts proximal to an intraductal papillary-mucinous adenoma with mild atypia of the branch duct type in the pancreatic body, with no relation between the two lesions. IDC was demonstrated as an extremely low-echoic mass resembling a cyst with an unclear margin on the initial endoscopic ultrasonography. We misinterpreted the low-echoic mass as a benign intraductal mucinous-papillary neoplasm (IPMN) based on findings of other imaging studies, and the patient was followed-up. The mass increased from 7 mm to 13 mm in diameter over 22 mo, and remained smaller than 10 mm in diameter for about 420 d. The tumor volume doubling time was 252 d. The Ki67 labeling index was 15.9%, similar to that described in previous reports. Hence, IDC may grow slowly while remaining small.

Prognosis of hepatocellular carcinoma accompanied by microscopic portal vein invasion

AIM:To investigate the prognostic factors in patients with hepatocellular carcinoma(HCC) accompanied by microscopic portal vein invasion(PVI).METHODS:Of the 267 patients with HCC undergoing hepatic resection at Aso Iizuka Hospital,71 had PVI.After excluding 16 patients with HCC that invaded the main trunk and the first and second branches of the portal vein,55 patients with microscopic PVI were enrolled.RESULTS:The patients with HCC accompanied by microscopic invasion were divided into two groups:solitary PVI(PVI-S:n = 44),and multiple PVIs(PVI-M:n = 11).The number of portal vein branches invaded by tumor thrombi was 5.4 ± 3.8(2-16) in patients with PVI-M.In cumulative survival,PVI-M was found to be a significantly poor prognostic factor(P = 0.0019);while PVI-M and non-anatomical resection were significantly poor prognostic factors in disease-free survival(P = 0.0213,and 0.0115,respectively).In patients with PVI-M,multiple intrahepatic recurrence was more common than in the patients with PVI-S(P = 0.0049).In patients with PVI-S,non-anatomical resection was a significantly poor prognostic factor in disease-free survival(P = 0.0370).Operative procedure was not a significant prognostic factor in patients with PVI-M.CONCLUSION:The presence of PVI-M was a poor prognostic factor in patients with HCC,accompanied by microscopic PVI.Anatomical resection is recommended in these patients with HCC.Patients with HCC and PVI-M may also be good candidates for adjuvant chemotherapy.